The continuous persistence and the recent resurgence of tuberculosis emphasize the need for the development of an improved vaccine. Potential strategies for the development of such a vaccine include the use of M. tuberculosis secreted proteins, which are present in culture filtrates (CF). We have immunized rhesus macaques with M. tuberculosis H37Rv LAM-free CF. Groups of two animals each received CF in absence of adjuvant, CF resuspended in RIBI adjuvant or alum-precipitated CF. All animals were given two monthly intramuscular injections of the immunogens, followed by a single intranasal immunization of either CF or CF and cholera toxin B subunit. All single doses of immunogens consisted of 1 mg CF. Preliminary results from these studies indicate that, following the above described immunization protocol, the CF immunogenicity in rhesus macaque is limited. The tuberculin skin test was negative in all animals throughout and after the series of immunizations. No significa nt in vitro cellular proliferative responses to CF could be detected. Antibody responses were present at a very low level in animals immunized without adjuvant. However, animals inoculated with alum-CF or RIBI-CF produced moderate antibody responses consistently directed to multiple specific antigens exhibiting a broad range of molecular weights. Intranasal immunizations induced increased production of specific antibodies in animals previously immunized with CF-adjuvant. Additional immunization protocols and adjuvant formulations should be tested for the identification of immunodominant M. tuberculosis secreted antigens in rhesus macaques. Therefore, we have immunized four additional macaques to assess whether or not presence of LAM in the immunogens may induce an increase in specific immune responses.